When I bought our Bruce 30kg I asked about swivels at a large local marine supply. I knew the fellow behind the counter had been around for a long time and had talked to him about different pieces of gear from time to time, a very knowledgable guy. Instead of giving me an answer about swivels he reached under the counter and brought out a horribly mangled and broken, large, heavy duty anchor
swivel (an expensive stainless one, don't remember the brand). I don't use one. Even with all chain rode
and anchoring extensively I don't have any problems getting the anchor
up into the roller.